CN-121994359-A - Atomic thermometer with traceable physical constant based on fluorescence detection and method

CN121994359ACN 121994359 ACN121994359 ACN 121994359ACN-121994359-A

Abstract

The invention relates to a physical constant traceable atomic thermometer and a method based on fluorescence detection, wherein a low n-state atomic radiation field sensor is reversely overlapped and propagated in a rubidium atomic steam pool through 780 nm detection light and 776 nm decoration light to form electromagnetic induction transparency, a Redberg atomic radiation field sensor is overlapped and propagated in the same direction with the decoration light through 1263 nm coupling light to form three-photon electromagnetic induction transparency, atoms transition to adjacent energy levels under the induction of blackbody radiation and generate fluorescence, and the spectral density characteristics of the blackbody radiation in a plurality of characteristic wave bands are synchronously extracted to a unified quantum sensing platform through the co-fluorescence detection of high-principal quantum number atoms and low-principal quantum number atoms. And directly fitting the absolute temperature of the object according to the Planck blackbody radiation law through the acquired wide-spectrum radiation spectral density data. High-precision absolute temperature measurement which is independent of external calibration and can effectively inhibit the influence of surface emissivity.

Inventors

ZHANG JIANAN
JIA FENGDONG
WANG JINGHUI
MENG FEI
WANG QIANG
LIU YUQING
Xu Zhenlu
ZHANG JIANWEI
ZHONG ZHIPING

Assignees

贾凤东
中国科学院大学

Dates

Publication Date: 20260508
Application Date: 20251211

Claims (10)

1. The atomic thermometer is characterized by comprising a low n-state atomic radiation field sensor, a blackbody, a Redberg atomic radiation field sensor, a photoelectric detector, a fluorescence collection device and a spectrometer; The low n-state atomic radiation field sensor is used for reversely and coincidently transmitting the detection light of 780 nm and the decoration light of 776 nm in a rubidium atom steam pool, so that atoms are excited from a ground state 5S 1/2 to a 5P 3/2 and then to a 5D 5/2 to form electromagnetic induction transparency; Blackbody is used to emit blackbody radiation, and under the induction of blackbody radiation, the 5D 5/2 atom transitions to the adjacent 6, 7, 8P 3/2 energy level, and then spontaneous emission will produce fluorescence of 420, 360, 335 nm in the ground state 5S 1/2 ; The high n-state Redberg atomic radiation field sensor is used for exciting atoms from 5D 5/2 to a Redberg state n F 7/2 by using 1263 nm laser as coupling light and co-directionally coincident propagation of decoration light on the basis of the low n-state atomic radiation field sensor to form three-photon electromagnetic induction transparency; Blackbody is used to emit blackbody radiation, and atoms transition from nF 7/2 to an adjacent energy level (n+1) or (n+2) D 5/2 under the induction of blackbody radiation and spontaneously radiate to produce fluorescence of about 480 nm; the photoelectric detector is used for detecting 780-776-1263 three-photon electromagnetic induction transparency; the fluorescence collection device is used for converging the divergent fluorescence signals on a photosensitive surface of the spectrometer; The spectrometer is used for carrying out spectrum resolution on the converged fluorescent signals so as to obtain intensity information corresponding to different radiation fluorescence; And converting the fluorescence intensity information into blackbody radiation spectral density information according to a pre-stored formula, and performing blackbody radiation spectral fitting to obtain the temperature corresponding to the detected radiation.
2. The fluorescence detection-based physical constant traceable atomic temperature meter according to claim 1, wherein the low n-state atomic radiation field sensor comprises a 780 nm laser, a 776 nm laser, a saturated absorption spectrum device, a 780-776 two-photon EIT spectrum device, at least two fiber couplers and a rubidium atom vapor cell, wherein the 780 nm laser is used for generating 780 nm laser light to drive rubidium atoms in the rubidium atom vapor cell to excite from a ground state 5S 1/2 to an excited state 5P 3/2 ; the laser 776 nm is used for generating laser 776 nm to drive rubidium atoms in the rubidium atom steam pool to be excited from an excited state 5P 3/2 to a decorated state 5D 5/2 , the laser 780 nm is used as detection light, the laser 776 nm is used as decorated light, the saturated absorption spectrum device is used for locking the frequency of the laser 780 nm, the 780-776 two-photon EIT spectrum device is used for locking the frequency of the laser 776 nm, the 780 nm laser and the 776 nm laser are respectively arranged on two sides of the rubidium atom steam pool and emit laser along the direction perpendicular to the rubidium atom steam pool, an optical fiber coupler is respectively arranged on two sides of the rubidium atom steam pool, the detected light 780 nm and the decorated light 776 nm are oppositely superposed and propagated in the rubidium atom steam pool, and the rubidium atoms are sequentially excited from a base state 5S 1/2 to a 5P 3/2 and are excited to a 5D 5/2 , and electromagnetic induction transparency is formed.
3. The fluorescence detection-based physical constant traceable atomic thermometer of claim 2, wherein the probe light is locked to the 5S 1/2 to 5P 3/2 transition by saturation absorption spectroscopy.
4. The fluorescence detection-based physical constant traceable atomic temperature meter according to claim 2, wherein the decoration light is transparently locked on the transition from 5P 3/2 to 5D 5/2 through two-photon electromagnetic induction.
5. The fluorescence detection-based physical constant traceable atomic thermometer according to claim 1, wherein the high n-state Redburg atomic radiation field sensor comprises a 1263 nm laser, the 1263 nm laser emits laser light in a direction parallel to a rubidium atomic steam cell, and based on the low n-state atomic radiation field sensor, the 1263 nm laser light is used as coupling light to co-directionally coincide with the decoration light to transmit, so that atoms are excited from 5D 5/2 to the Redburg state nF 7/2 , and three-photon electromagnetic induction transparency is formed.
6. A physical constant traceable atomic temperature measurement method based on fluorescence detection is characterized in that the method realizes absolute temperature measurement through the physical constant traceable atomic temperature meter based on fluorescence detection according to any one of claims 1 to 5, and the method comprises the following steps: S1, utilizing 780 nm detection light and 776 nm decoration light to oppositely and coincidently propagate in a rubidium atom steam cell to form a low-n-state atomic radiation field sensor, and utilizing 1263 nm coupling light and 780 nm detection light to oppositely and coincidently propagate in the rubidium atom steam cell to construct a Redberg atomic radiation field sensor; s2, selecting a corresponding quantum measurement path for measurement according to the measured temperature corresponding to the blackbody radiation center wavelength, wherein the quantum measurement path comprises a low n-state energy level measurement path and a high n-state Redberg state energy level measurement path; s3, locking a laser system, namely locking the frequency of related lasers according to the selected quantum measurement path; s4, rubidium atoms in the blackbody radiation rubidium atom steam pool are induced to adjacent energy levels by blackbody radiation and spontaneously radiate to generate fluorescence; S5, collecting and detecting fluorescent signals, and converting the fluorescent intensity into blackbody radiation spectral density information; s6, performing blackbody radiation spectrum fitting to obtain the temperature corresponding to the detected radiation.
7. The method for atomic temperature measurement based on fluorescence detection with traceable physical constants of claim 6, wherein in step S2, for temperatures with measured temperatures higher than a first preset temperature, a low n-state energy level measuring path is selected for temperature measurement, and for temperatures with measured temperatures lower than a second preset temperature, a high n-state Redberg state energy level measuring path is selected for temperature measurement.
8. The method of atomic temperature measurement based on fluorescence detection with traceable physical constants of claim 7, wherein in step S3, 780 nm laser is locked at the transition of 5S 1/2 →5P 3/2 , 776 nm laser is locked at the transition of 5P 3/2 →5D 5/2 , and 1263 nm laser is locked at the transition of 5D 5/2 →40F 7/2 .
9. The method of atomic temperature measurement based on fluorescence detection with traceable physical constants of claim 7, wherein step S3 turns on 1263 nm the laser and locks only when a high n-state Redberg level measurement path is selected.
10. The method for atomic temperature measurement based on physical constant traceability of fluorescence detection according to any of claims 6 to 9, wherein the relationship between fluorescence intensity and blackbody radiation temperature in step S5 is calculated according to the following formula: (1) Where S is the intensity of the detected fluorescence, N is the total number of atoms involved in the interaction, η is the response efficiency of the detector, Γ is the spontaneous emission rate of the energy level at which the fluorescence is generated, p is the distribution over the corresponding energy levels, determined by the blackbody radiation induced transition, as a function of temperature T.

Description

Atomic thermometer with traceable physical constant based on fluorescence detection and method Technical Field The invention belongs to the field of temperature measurement, and particularly relates to a physical constant traceable atomic thermometer based on fluorescence detection and a method thereof. Background The accurate measurement of the absolute temperature of an object has important applications in the fields of industrial process control, scientific experiments, medical diagnosis, and the like. For example, non-contact temperature measurement based on blackbody radiation law is a main means for measuring the temperature of high-temperature, moving or easily polluted objects, and is centered on accurately sensing the intensity of electromagnetic waves radiated by the objects. The traditional radiation temperature measurement technology depends on a single classical detector (such as an infrared thermometer and a microwave radiometer) working in a specific wave band, which has inherent limitations that firstly, measurement accuracy cannot be traced to a basic physical constant, a blackbody with known temperature must be used for frequent and complex recalibration to resist detector drift, secondly, the measurement result of the single wave band is seriously influenced by unknown emissivity of the surface of an object, a system error which is difficult to correct is introduced, thirdly, if the blackbody radiation spectrum is acquired to invert the real temperature or correct the emissivity influence, a plurality of independently calibrated detector systems aiming at different wave bands must be integrated in the prior art, so that the device is complex, high in cost and difficult to ensure consistency among channels. Compared with the traditional radiation sensor, the microwave electric field quantum sensor based on the Redberg atoms has the advantages of high sensitivity, wide frequency band, electromagnetic interference resistance, no need of external calibration, traceability to basic physical constants and the like, and has attracted wide attention in the field of electromagnetic sensing in recent years. Although the reed-burg atom based quantum sensor provides a new approach to self-calibrating absolute radiometric measurement, the existing solutions have significant limitations themselves. The current research is limited to the precise microwave measurement by using single and high-excitation-state (high n) Redberg atoms, and the sensitive frequency band is mainly concentrated in the range from microwave to millimeter wave, corresponding to the low-temperature range of the emitter of the blackbody. Meanwhile, no technical scheme for directly measuring the blackbody radiation temperature by using a Redberg atom microwave receiver is disclosed at present. The National Institute of Standards and Technology (NIST) of 2025 explored a scheme for measuring temperature using the fluorescence intensity of radiation after the induction of rubidium atoms with low number of main quanta n by blackbody radiation, but essentially did not get rid of a single point measurement scheme, measured only the intensity of single wavelength blackbody radiation of 12.2 μm, and failed to capture shape information of blackbody radiation spectrum per se. The absolute temperature is inverted only by means of single-point measurement of microwave/millimeter wave bands, and the energy main peak information of blackbody radiation cannot be captured essentially, so that the inversion accuracy and reliability are fundamentally restricted, and the theoretical advantage of the atomic sensor from tracing to a basic physical constant cannot be fully exerted. In addition, the existing schemes also fail to solve the systematic difficulty of how to achieve synchronous measurement of broad spectrum radiation on a unified and compact quantum platform, and the information dimension and application potential thereof are severely limited. Disclosure of Invention Aiming at the technical defects existing in the prior art, the invention aims to provide a physical constant traceable atomic thermometer and a method based on fluorescence detection, which synchronously extract spectral density characteristics of blackbody radiation in a plurality of characteristic wave bands (particularly an infrared micron wave band where an energy main peak is located and a millimeter wave band with strong penetrability) onto a unified quantum sensing platform by utilizing common fluorescence detection of high-main quantum number (high n) atoms and low-main quantum number (low n) atoms. At this time, the absolute temperature of the object can be fitted directly according to the Planckian blackbody radiation law by the acquired wide-spectrum radiation spectral density data. In order to achieve the above purpose, the invention adopts the technical scheme that: in a first aspect, the invention discloses an atomic thermometer with traceable physical constants based